Telephone system



Sept. 5, 1933.

S. UDA ET AL TELEPHONE SYSTEM Filed April 20. 1932 5. 00/1 lNl/ENTORS OKURA ATTORNEY Patented 5, 1%335 rate TELEPHONE SYSTEM Shuliichi Uda, Tamagawalnura, Ebara District,

Tokyo-Fir, waliu, Tokyo, Japan,

and Teiichiro Okura, Koishikaassignors to Western Application April 20, 1932, Serial No. 606,322, and in Japan August 4, 1931 10 Claims.

This invention relates to telephone systems and particularly to improvements in automatic telephone systems.

Its object is to improve and simplify automatic systems in which preferential calls may be made to busy subscribers lines.

Heretofore systems have been provided in which an operator may set up, a connection to a busy line and leave'it in such a condition that the line would be automatically seized when the busy condition is removed. Other systems have been provided in which when a calling subscribers line j is connected to a wanted subscribers linethe idle or busy condition of the wanted subscribers line is tested and the called subscriber when-busy notifiedthat another connection with his line is desired. Still other systems have been provided whereby a final switch in the automaticsystem'is so modified that a desired subscribers line is seized regardless of its busy condition and whereby the usual busy signal isrendered ineffective. A feature of the present'invention resides in means whereby a second calling subscriber may set up a connection to a busy line, receive a busy signal and then by dialing a certain number, for example 1, prepare said connectionto ring over the desired subscribers line and establish the connection to this line when the called subscriber releases the previous connection.

Another feature of this invention is a preferential call arrangement of this kind in which calling subscribers lines may be connected toa called subscribers line in the sequence in which the calls are made, a new connection being established as .soon as the preceding connection has been released.

Another feature of the invention is a means whereby when a calling subscriber dialsthe nuinber 1, the busy signal is removed from this subscribers line provided that no other calling subscriber is awaiting a connection and whereby said busy condition remains in ;case another calling subscriber is awaiting a connection until this previous calling subscriber has establisheda connection as the called subscribers line becomes idle when the busy signal is removed.

Referring now to the drawing, at A is shown a calling subscribersline in diagrammatic form associated with a connector circuit shown at C in detail. At B is shown a called subscribers line which terminates at terminals in-the bank of con nector C and also in terminals at connectors D and E, the brushes of which only are shown.

Descriptions will now be made of a call from subscriber A through connector C to the sub- 7 1 contacts 14.

scriber B assuming that subscriber B is busy, that is, engaged for example by a calling subscriber through connector D or E, followed by description of the operation of connector C when subscriber B becomes idle and the calling subscriber A made through operations in connector C call subscriber B and be connected for conversation. A description will also be made of the operation of connector C in case the called subscriber B is already engaged by,for example, a connection through A circuit is thereby completed for the operation 7 of relay 10 from battery and ground through its windings, contacts of relay 9 and the. calling subscribers loop over the tip and ring conductor. The operation of relay l0 closes an obvious circuit for the operation of relay 11. When the subscriber A now dials the next digit, relay 10 responds to theiirnpulses thereof and a circuit is closed upon the first release of relay 10 for the operation of vertical magnet 12 and relay 13 as follows: Battery windings of vertical magnet 12 and relay 13 in series, vertical off-normal contacts 14, inner armature and front contact of relay 13, armature and bacl: contact of relay 10 to ground. This causes the operation of relay 13 and vertical magnet 12. When the first step is taken the vertical off-normal contacts 14 change the circuit for relay 13 and magnet 12,, to pass through the lower armature and front contact of relay 13. The succeeding. impulses cause the vertical magnet 12 to step the brushes of the connector C to the desired vertical-position and while these impulses are being transmitted relay 13 which is slow to release remains operated. 'At the end of this series of impulses relay 13 releases and can not again be operated due to the change in the vertical off-normal When the last digit is transmitted,the first impulse causes the operation of the rotary magnet 15 and relay l6 frombattery in parallel through the lower inner armature and back contact of relay 17, lower inner armature and back contact of relays 18 and 13 in'series, vertical offnormal contacts 14, lower armature and front contact of relay 11 and armature and back con tact of relay 10 to ground, During the succeed-f operated while the line of the called subscriber B is engaged. This ground causesthe operation of relay 18 before relay 16 has time to release. The circuit may be traced frombattery, winding of relay 18, upper inner armature and back centact of relay 1'7, upper armature and front contact of relay 16, brush S, terminal 20 to ground at the armature and front contact 'of relay 21. When relay 16 new releases, a locking circuit is established for relay 18 from battery, winding of this relay, upper inner armature and back contact of relay 1'7, upper make before break contacts of relay 16, upper armature and tront contact oi relay 1 8, to ground at the upper armature and front contact of relay l3. Relay 18 in oper ating closes a circuit from the busy tone source at 22, lower armature and back contact of relay 23, third lower armature and front contact of relay 18, second lower armature and back contact of relay '16, condenser 24 over the ring con" ductor to the calling subscriber A.

If new the calling subscriber desides to wait for the called subscriber at B to become idle he will dial one impulse and thereby cause relay to to be momentarily released. When the ground is "applied at the armature and back contact of relay 1 0,-relay 23 is partially operated over a circu-it from battery, upper winding of this relay, second lower armature and front contact of relay 18, lower armature and back contact of relay 1 3,

7 vertical off-normal contacts 14, lower armature and front contact of relay '11, 'to ground at the armature and back contact of relay 1'0. This partial operation of relay 23 only causes a connection to be made between the armature and front contact at 25 and when relay it again operates 'a circuit is completed from battery, upper and lower windings of relay 23, contacts 25, second lower armature and back contact of relay 17 to ground at the lower outer armature and front contact of relay 11, thus causing the norm plete operation of relay 2'3. Relay '23 in operating completely opens at the lower armature and back contact a connection from the busy tone source 22 to the calling subscribers line and thus discontinues the busy tone to thesubscriber A. The operation' of relay 23 also closes a connectionto ground for "rush S2 to prepare the circuit of this connector .ior seizing the called subscriber's rline B when it becomes idle. This ground will be applied from the lower outer armature and back contact of relay '17, second upper armature and front contact of relay 23 to brush S2. The calling subscriber A wiil now wait until the called subscriber 28 becomes idle.

When the called subscriber releases the -p'revious connection, the ground is removed from terminal 20. The removal of "this ground causes the battery through the 'cut-oif relay 26 to cause the operationof relay 1"? over a circuit from battery, winding of cut-01f relay 26, terminal 20, brush S1, upper outer armature and back contact of relay 16, upper winding of relay 17, upper outer armature and front contact of relay 23 to ground at the upper armature and front contact of relay l1. Relay 17 in operating provides a locking circuit from battery, lower winding and lower second outer armature and front contact of this relay to ground at the lower outer armature and front contact of relay 11. The operation of relay 17 causes the release of relays l8 and 23. Relay 18 in releasing provides a holding circuit .for relay 17 to ground at relay 11 at its upper armature and back contact; Relay 23 on releasing opens the connection to the ground at the lower outer armature and back contact of relay 17 so that another waiting connector awaiting a connection to called subscriber B may function to secure a connection to this subscriber when the connection to connector B from subscriber A is released, as will hereinafter be described. The operation of relay 1'? now applies ringing current to the -calledsubscriber B from the ringing source 28, upper winding of ringing relay 19 and its upper armature and back contact, upper outer armature and front contact of relay 17 over the tip conductor to the called subscribers bell and back over the ring conductor, third lower ar1nature and front contact of relay 1? and the second lower armature and back contact of relay 18 to ground. When the calledsubsoriber at B answers the call, relay 19 operates to connect the calling and called subscribers over the tip and ring conductors and conversation between these two subscribers may now begin. Relay 19 'is held operated through its lower winding under control of relay 11. If after the subscriber A has made a call, other subscriber makes a call for subscriber B,

this subscriber will be Waiting his turn to get a connection to the subscriber B. In this case, the connector through which this connection will be established will receive a ground from the armature and front contact of relay 21 on its terminal corresponding to terminal 20. This causes the relay corresponding to relay 18 to be operated in the same manner as hereinbefore described. It should be observed that in this case the relay corresponding to relay 23 can only be partially operated when the relay corresponding to relay 18 is operated as a result of this second calling subscriber dialing one impulse. This is due to the 'fact that the lower winding of this relay is short-circuited over a circuit as follows: battery,

upper winding of the relay corresponding to relay 23, lower outer armature and front contact of the relaycorresponding to relay 1 8, second upper armature and back contact of therelay corresponding to relay 23, the brush corresponding to brush S2, to ground supplied over the brush'fis of connector C as hereinbefcre describe This ground on terminal S2 is maintained until the called subscriber at B becomes idle and relay 23 in releasing removes it. The failure of the relay H scriber B. When the first calling subscriber releases the connection to subscriber B as hereinbefore described the ground on terminal 29 is removed by the release of relay The second calling su'bscribers connector will then operate as hereinbefore described tocause the relay cor responding to relay '23 to be fully operated and partly establishing a connection from the second remove the busy tone from the line. This indicates to the second calling subscriber-that his turn has come tocomplete the connection'to the called subscriber B and the connector circuit for this second subscriber will now function as connector C under the same'circumstances as hereinbeforedescribed to complete the connection.

What is claimed is:-

1. In a telephone system, a first calling subscribers line, a second calling subscribers line, a called subscribers line, means for establishing a connection between the first'calling subscribers line and the called subscribers line, means for thereafter partially establishing a connection between the second calling subscribers line and the called subscribers line, and means controllable any time before or after the release of the first mentioned connection by the second calling subscriber for completing the second mentioned connection on the release of the first mentioned connection. 7

2. In a telephone system, a first calling subscribers line, a second calling subscribers line, a called subscribers line, means for establishing a connection between the'first calling subscribers line and the called subscribers line, meansresponsive to a certain code signal from the second calling subscribers line for partially preparing a connection between said second calling subscribers line and the called subscribers line, and means for completing said last mentioned connection operative on the release of the first mentioned connection.

3. In a telephone system, a calling subscribers line, a called subscribers line, means for partially establishing a connection between said calling subscribers line and said called subscribers line if said called subscribers line is busy and for transmitting a busy tone to the calling subscribers line, means for transmitting'a code signal from said calling subscribers line over said partially established connection, means responsive to said code signal for removing said busy signal, and means operative when the called subscribers line becomes idle for completing the partially established connection between said subscribers line.

e. In a telephone system, a first calling subscribers line, a second calling subscribers line, a called subscribers line, means for establishing a connection between the first calling subscribers line and the called subscribers line, means forpartially establishing a connection between the second calling subscribers line and the called subscribers line, means responsive to the establishing of said partial connection for transmitting a busy tone to the second calling subscribers line, means for transmitting a code signal from the second calling subscribers line over said partially established connection, and means responsive to said code signal for removing said busy tone, means thereafter responsive to therelease of said first mentioned connection for transmitting ringing current to the called subscribers line from the partially established connection, and means responsive to the called subscriber answering this ringing by removing his receiver from the hook for completing said partially established connection to the called subscribers line from the second calling subscribers line.

5. In a telephone system, a first calling subscribers line, a second calling subscribers line, a called subscribers line, means for establishing a connection between the first calling subscribers line and the called subscribers line, means for subscribers line to lineterminals of the called subscribers line, means responsive to said sec- 0nd connection for transmitting a busy time to said second calling subscribers line, meansiior transmitting from said second calling subscribers line a current impulse over the partly established 'connection,'means responsive to said impulse for discontinuing the busy tone and for preparing the partially established connection for completion to the called subscribers line when it becomes idle, means responsive to thecalled subscriber hanging up his receiver for releasing the connection established from the first calling subscriber and for transmitting ringing current tothe called subscribers line over the terminals to which a connection has been partially prepared from the second calling subscribers line, and means responsive to the called subscriber answering said ringing by removing his receiver from theswitchhook for completing a talking connection between the second calling subscribers line and the called subscribers line.

6. In a telephone system, calling subscribers lines, a called subscribers line, means for establishing connections from said calling subscribers lines to said called subscribers line in sequence in the order in which suchattempts are made, a

succeeding connection is completed as soon as a preceding one is released, said means being'op eratively controlled by the individual subscribers making the calls;

7. In a telephone system, calling subscribers lines, a called subscribers line, means for establishing connections from said calling subscribers linesto said called subscribers line in sequence in the order in which such attempts are made, a succeeding connection being completed as soon as a preceding connection has been released, said means being responsive to signals transmitted from the calling subscribers lines.

8. In a telephone system, calling subscribers lines, acalled subscribers line, means for partially establishing connections from said callingsubscribers lines toward the called subscribers lineif said called subscribers line is busy, and means for completing said connections in the order in which the attempts were made to establish such connections, a connection from a succeeding calling subscriber being completed in 3 response to the release of the connection that has been previously completed in the sequence.

" 9. In a telephone system, calling subscribers lines, a called subscribers line, means for partially establishingaconnection between afirst calling subscribers line and the called subscribers line if the called subscribers line is busy and for completing said connection when the called subscribers line becomes idle, means for partially establishing a connection between a second calling subscribers line and the called subscribers line While said called subscribers line is. busy due to a connection prior to the first calling subscriber having attempted a connection or U due to the first calling subscriber having established the connection to the called subscribers line, means for transmitting a busy tone to said second calling subscribers line, means for transmitting a code signal from said second calling subscribers line over the partially established connection from said second calling subscribers line, means responsive when said first calling subscribers line connection has been completed for removing the busy signal to the second calling subscribers line, and means for completing the connection from the second calling subscribers line when the first calling sub scribers connection has been released.

10. In a telephone system; a first calling subscrib'ers line, a second calling subscribers line, a called subscribers line, means for establishing a connection between the first calling subscribers line and the called subscribers line, means for thereafter partially establishing a connection between the second calling subscribers line and 

